# Tolerance Parameter Fix - Update Notes

## What Was Wrong

The original tolerance parameter used raw Euclidean distance in RGB space (0-255 scale), which was unintuitive:
- Max possible distance in RGB = sqrt(3 × 255²) ≈ 441
- A tolerance of "30" was actually very strict (only ~7% of max distance)
- For antialiasing around text, you needed values like 150+ which wasn't obvious

## What's Fixed

**New Scale: 0-100** (percentage-based)
- 0 = exact color match only
- 30 = 30% of maximum color distance (default, RECOMMENDED)
- 100 = maximum tolerance

**Why This Matters for Antialiasing:**

Example: Gray layer (150,150,150) with black text (0,0,0)
- Antialiasing creates intermediate colors: (75,75,75), (100,100,100), (125,125,125)
- Distance from gray (150,150,150) to (75,75,75) = sqrt(3 × 75²) ≈ 130
- Old scale: You'd need tolerance ~130 (not intuitive)
- New scale: tolerance 30-45 captures these (makes sense!)

## Updated Recommendations

```bash
# Default - good for most diagrams
python layer_extractor.py diagram.pdf -t 30

# Heavy antialiasing (small text, complex diagrams)
python layer_extractor.py diagram.pdf -t 45

# Extreme antialiasing (compressed PDFs, low quality)
python layer_extractor.py diagram.pdf -t 60

# Very strict (clean diagrams, no antialiasing)
python layer_extractor.py diagram.pdf -t 15
```

## Key Point

**If you see missing pixels around text or edges → INCREASE tolerance (not decrease!)**

The antialiased pixels are "far" from the target color in RGB space, so they need higher tolerance to be captured.

## Test Your Diagram

Start with default (30), then:
- Missing pixels/gaps around text? → Try 45
- Still missing details? → Try 60  
- Layers bleeding together? → Try 20